Rotary kilns of the type having a plurality of planetary cooler tubes for rotation with it to receive and cool the product such as cement clinker from the kiln are well known.
In some known rotary kilns, the planetary cooler tubes are preferably retained in position around the rotary kiln by brackets welded onto the kiln shell. Each bracket is situated entirely within an angular space having its vertex in the kiln axis and contains the respective cooler tube. In such planetary cooler tube suspensions, the kiln shell is subjected to powerful variable stresses along the base of the bracket. After a period of operation, these stresses can lead to fracture of the kiln shell, particularly in the area between two adjacent brackets. The kiln shell, at one bracket, is exposed to a radially outwardly directed force and, at the opposite bracket, to a radially inwardly directed force.
In an attempt to overcome this problem, it has been suggested to allow the base of the brackets to extend into the annular space of an adjacent cooler tube. One such development includes a ring member equipped with saddles and encircling the kiln entirely. In this manner momentum impacts on the kiln shell are avoided.
However, the use of such a ring member encircling the kiln is not troublefree. Since the ring is welded onto the kiln, problems arise from the dissimilar heat expansion of the hot kiln shell and the somewhat cooler outer ring. Although the ring member can be mounted loosely on the kiln shell, in practice, this causes the ring to be supported by the uppermost portion of the kiln shell. Consequently the kiln shell is subjected to a radially inwardly directed force that deforms the circular cross-section of the kiln shell to that of an ellipse thus causing undesirable stresses on the lining of the kiln. I have invented an improved planetary cooler tube suspension which avoids the above-noted limitations of the prior art suspensions.